Submission #1122748

#	Time	Username	Problem	Language	Result	Execution time	Memory
1122748		gdragon	K blocks (IZhO14_blocks)	C++20	0 / 100	1 ms	1096 KiB

blocks

#include <bits/stdc++.h>
using namespace std;
#define TASK "long"
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define GETBIT(mask, i) ((mask) >> (i) & 1)
#define MASK(i) ((1LL) << (i))
#define SZ(x) ((int)(x).size())
#define mp make_pair
#define CNTBIT(mask) __builtin_popcount(mask)
template<class X, class Y> bool maximize(X &x, Y y){ if (x < y) {x = y; return true;} return false;};
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y) {x = y; return true;} return false;};
typedef pair<int, int> ii;
const int N = 1e5 + 5;
const int inf = 1e9 + 7;
const long long INF = (long long)1e18 + 7;
const int mod = 1e9 + 7;
void add(int &x, int y) {x += y; if (x >= mod) x -= mod;}
void sub(int &x, int y) {x -= y; if (x < 0) x += mod;}
int mul(int x, int y) {return 1LL * x * y % mod;}
// -----------------------------------------//
const int LOG = 17;
int n, k;
int f[N][LOG + 2], a[N], dp[2][N];
void read() {
    cin >> n >> k;
    for(int i = 1; i <= n; i++) cin >> a[i];
}
void build() {
    for(int i = 1; i <= n; i++) f[i][0] = a[i];
    for(int j = 1; j <= LOG; j++) {
        for(int i = 1; i + MASK(j) - 1 <= n; i++) f[i][j] = max(f[i][j - 1], f[i + MASK(j - 1)][j - 1]);
    }
}
int getMax(int l, int r) {
    int k = log2(r - l + 1);
    return max(f[l][k], f [r - MASK(k) + 1][k]);
}
int cost(int l, int r) {
    // cerr << l << ' ' << r << ' ' << getMax(l, r) << endl;
    return getMax(l, r);
}
void calDp(int l, int r, int optl, int optr) {
    if (l > r) return;
    int mid = (l + r) >> 1;
    int best = optl;
    for(int i = optl; i <= min(mid, optr); i++) {
        // cerr << mid << ' ' << i << endl;
        if (minimize(dp[0][mid], dp[1][i - 1] + cost(i, mid))) {
            best = i;
            // cerr << mid << ' ' << g << ' ' << dp[mid][g] << endl;
        }
    }
    calDp(l, mid - 1, optl, best);
    calDp(mid + 1, r, best, optr);
}
void solve() {
    build();
    for(int i = 0; i <= n; i++) {
        for(int j = 0; j < 2; j++) dp[j][i] = inf;
    }
    dp[0][0] = 0;
    for(int i = 1; i <= k; i++) {
        swap(dp[0], dp[1]);
        for(int j = 1; j <= n; j++) dp[0][j] = inf;
        calDp(1, n, 1, n);
    }
    cout << dp[0][n]; 
}
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
    int test = 1;
    // cin >> test;
    while(test--) {
        read();
        solve();
    }
    return 0;
}

Compilation message (stderr)

blocks.cpp: In function 'int main()':
blocks.cpp:76:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
blocks.cpp:77:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 14
• Subtask 2: 0 / 18
• Subtask 3: 0 / 21
• Subtask 4: 0 / 47